Development And Research Of EPS For Commercial Vehicles Based On DSPACE

As a new high-tec, the Electric Power Steering(EPS) represents the future of automotive steering technology and conforms to the modern vehicle development of “Energy-saving, Environmental Protection, Safty and Comfortable”. And the applied range of EPS has expended to commercial vehicle from the initial micro-cars and passenger cars. The process of EPS development is very long and complex. Along with the advance of computer simulation technology, the rapid control prototyping platform has become an important means for research and development of the automotive electronic control system including EPS. The platform can greatly shorten the product development cycle and reduce the cost of product development through model modification, calibration parameters, automatic code generation and real-time experiment, etc.The thesis chooses the key components of EPS used for a medium truck with a capacity of 4 ton. According to the parameters and the characters of the the target model, the paper establish the mathematical model of five degrees of freedom. Based on the software of Simulink, the thesis establishes the EPS simulation model which is verified through the simulated analysis of transient and steady state performance of the vehicle.This paper deeply researches the curve of assist characteristic and control strategies when vehicle under different operating conditions. Aimed at the design of motor current controller, the closed loop PID control algorithm is presented based on the target current. The additional algorithms of incomplete differential and Limit-stop integral can effectively avoid system shock, and improve the dynamic performance of the system by simulation tests. In order to test and fully validate the correctness and validity of EPS control arithmetic and logic code, this thesis builds a EPS rapid control prototyping(RCP) platform of semi-physical simulation by dSPACE real-time system, then respectively tests the characteristics of current step response, torque output signal and current output signal through the different test parameters setting by PC software of ControlDesk. The results show that the designed EPS control system can achieve function of assist successfully, and ment the control requirement.